200 Mr. E. Saunders' Synopsis of 



characters seem to lie in the shape of the face and meta- 

 thorax, and the sculpture and puncturation of the various 

 portions of the insect ; but it requires great care and 

 very minute examination in some cases to refer an indi- 

 vidual with certainty to its proper species, especially in 

 the group of minutus, nitidiusculus, &c. 



This is amongst the most difficult of our British 

 genera of Aculeates to tabulate, and the tables I have 

 prepared are far from satisfactory ; still I hope they will 

 be of some use as an aid to distinguish the species. I 

 have divided the genus into six divisions : — 



(2) 1. White pilose bands of the abdomen situated on the 



apical margins of the segments . . . . . . Div. I. 



(1) 2. White pilose bands of the abdomen, when present, 

 situated on the basal margins of the segments. 

 (10) 3. Species not small and aeneous. 



(5) 4. Large or medium-sized species ; abdomen deep 



black, with conspicuous pubescent spots or bands 

 on the 2nd, 3rd, and sometimes 4th segments ; 

 posterior margins of segments not testaceous . . Div. II. 

 (4) 5. Large or medium-sized species, with pale ajDical 

 margins to the segments ; or small species, with 

 scarcely any indication of the lateral spots, or 

 with the body entirely black. 



(7) 6. Hind margins of the segments rather widely tes- 



taceous-; ^ with the body smooth and glabrous 

 beneath ; J with the brow of the metathorax 

 sharply truncate, or with a more or less raised 

 line at the sides or very rugose, the brow not 

 smoother than the rest . . . . . . . . Div. III. 



(6) 7. (J with the segments of the body fringed beneath ; 



metathorax in the J rugose at the base, but 

 smoother towards the brow, which is more or less 

 rounded, and has no signs of a raised lateral 

 line. 

 (U) 8. Surface of thorax very smooth and polished, i3unc- 

 turation remote or very coarse and rugose ; meta- 

 thorax radiately rugose. In one species, j^u^icti- 

 collis, although the centres of the punctures are 

 remote, the actual punctures are so large that 

 their edges are pretty close together . . . . Div. IV. 



(8) 9. Surface of thorax rarely polished, but under a strong 



power seen to be finely rugose between the punc- 

 tures ; ijuncturation line and close . . . . Div. V. 



(3) 10. Species small and reneous, at least as regards the 



thorax . . . . . . . . . . . . Div. YI. 



